forked from Imagelibrary/rtems
dddc0557e5
This primarily included setting the state of the programmable outputs and the RX and TX FIFO depths. Moved all of the TX, RX, and RRA data structure initialization to before the hardware initialization. As part of this, the hardware initialization was consolidated. More than likely, some of this movement broke stuff. Used constants added to sonic.h which gave more logical names to some of the register bit settings. Switched to calloc to insure the data areas where initialized to 0. Commented out a panic check in the RX server which may or may not have been right. Increased the size of the CAM initialization area. It is possible that this could be decreased or code added to handle the management of multiple hardware addresses. Added sonic read and write register routines which aid greatly in debugging and provide the core for the eventual movement of this driver to libchip. Added debug code to the read and write register routines which can print the value read from or written to a register. This code also prints the register name which significantly eases reading the log.
#
# $Id$
#
Building RTEMS
==============
See the file README.configure.
Directory Overview
==================
This is the top level of the RTEMS directory structure. The following
is a description of the files and directories in this directory:
INSTALL
Rudimentary installation instructions. For more detailed
information please see the Release Notes. The Postscript
version of this manual can be found in the file
c_or_ada/doc/relnotes.tgz.
LICENSE
Required legalese.
README
This file.
c
This directory contains the source code for the C
implementation of RTEMS as well as the test suites, sample
applications, Board Support Packages, Device Drivers, and
support libraries.
doc
This directory contains the PDL for the RTEMS executive.
Ada versus C
============
There are two implementations of RTEMS in this source tree --
in Ada and in C. These two implementations are functionally
and structurally equivalent. The C implementation follows
the packaging conventions and hiearchical nature of the Ada
implementation. In addition, a style has been followed which
allows one to easily find the corresponding Ada and C
implementations.
File names in C and code placement was carefully designed to insure
a close mapping to the Ada implementation. The following file name
extensions are used:
.adb - Ada body
.ads - Ada specification
.adp - Ada body requiring preprocessing
.inc - include file for .adp files
.c - C body (non-inlined routines)
.inl - C body (inlined routines)
.h - C specification
In the executive source, XYZ.c and XYZ.inl correspond directly to a
single XYZ.adb or XYZ.adp file. A .h file corresponds directly to
the .ads file. There are only a handful of .inc files in the
Ada source and these are used to insure that the desired simple
inline textual expansion is performed. This avoids scoping and
calling convention side-effects in carefully constructed tests
which usually test context switch behavior.
In addition, in Ada code and data name references are always fully
qualified as PACKAGE.NAME. In C, this convention is followed
by having the package name as part of the name itself and using a
capital letter to indicate the presence of a "." level. So we have
PACKAGE.NAME in Ada and _Package_Name in C. The leading "_" in C
is used to avoid naming conflicts between RTEMS and user variables.
By using these conventions, one can easily compare the C and Ada
implementations.
The most noticeable difference between the C and Ada83 code is
the inability to easily obtain a "typed pointer" in Ada83.
Using the "&" operator in C yields a pointer with a specific type.
The 'Address attribute is the closest feature in Ada83. This
returns a System.Address and this must be coerced via Unchecked_Conversion
into an access type of the desired type. It is easy to view
System.Address as similar to a "void *" in C, but this is not the case.
A "void *" can be assigned to any other pointer type without an
explicit conversion.
The solution adopted to this problem was to provide two routines for
each access type in the Ada implementation -- one to convert from
System.Address to the access type and another to go the opposite
direction. This results in code which accomplishes the same thing
as the corresponding C but it is easier to get lost in the clutter
of the apparent subprogram invocations than the "less bulky"
C equivalent.
A related difference is the types which are only in Ada which are used
for pointers to arrays. These types do not exist and are not needed
in the C implementation.